# Is it possible to know the distance objects are from camera based on only knowing one object's height?

I am doing a project where I have to know distance a particular object is from camera. In the photo I only know one of the object's height, but I don't know how far away that object is and I don't know how tall are other objects. Is it possible to write a code or do some geometry to know other objects distances from camera using only the height of one object? For example I have an image where 5 meters away there is a box which is 1 meter high, I wanna know the distance to human who is 12 meters away, or to know a distance to a dog who is 7 meters away. Maybe you guys know any datasets or models which deal with the same problem as I am facing. Any help will be appreciated.

• No, it is impossible. Assume you see a circle, than in the image has 50 pixels of diameter (and a focal angle of 45º). The circle can have a real size of 1 meter and be at 1 meter distance, or 2 meters and be at 2 meters distance, ... . Impossible to know the real values. Oct 14 '20 at 19:03